Various biochemical parameters were investigated in the gerbil cerebral cortex both during and after occlusion of the common carotid artery. Ischemia produced large changes in the energy metabolites, cyclic nucleotides and certain putative neurotransmitters. There is an initial dramatic change in both energy metabolites and cyclic nucleotides after which the levels remain essentially constant. Recovery from the ischemic insult was marked by an apparent rapid restoration of energy metabolites, a short-term large increase in cyclic AMP and a significant reduction in enzyme activities of Na ion plus K ion activated ATPase and adenylate cyclase. The results on enzyme and metabolites seem to indicate that the recovery process is dependent on the intensity of the ischemic insult and that the recovery process is more than a mere reversal of the ischemic-induced events. The cyclic AMP fluctuations during ischemia and recovery were duplicated in brain slices from the gerbil. Theophylline increased gerbil mortality following an ischemic episode and also compromised the biochemical recovery process.